Moistureproof material and method of making same



25 ture content.

Patented Sept. 11, 1934 UNITED STATES MOISTUREPROOF MATERIAL AND METHOD OF MAKING SALIE William Hale Char-ch, Bulhlo, and William L. I-lyrlen and John C. Siemann, Kenmore, N. Y.,

assixnors to Du Pont Cellophane Inc., New York, N. Y.,

Company, a corporation of Delaware No Drawing. Application November 4, 1932, Serial No. 641,222 I 50 Claims. (Cl. 91-68) This invention relates to moistureproof materials and more particularly to a moistureproof material in which the moistureproof surface coating tenaciously adheres or is anchored to the base, and to the method of producing the same.

By the term "moistureproof as used in this specification is meant the ability of the coated material to resist the transmission or diffusion of moisture or water vapor therethrough to an exl0 tent at least 7,times, and preferably 10, 15, 20, 30, 50, 100 or even several hundred times, as great as that displayed by the uncoated base when tested in accordance with the test set forth in the Journal of Industrial and Engineering Chemistry, page 575, Vol. 21, N0. 6 (June, 1929).

Ordinary sheets or films of regenerated cellulose have been moistureproofed by coating with a composition comprising a cellulose derivative and a wax, with or without a gum or resin, and

optionally a plasticizer. This material is very elfective for wrapping products, such as bread, cakes, candies, cigars and the like, which are desired to be retained in their substantially original fresh condition without any change in mois- When products having an exceedingly large moisture or water content, such as cheese, butter, frozen fish, fresh vegetables, ice cream or the like, are wrapped in this material, the surface coating loosens and/or flakes oil with the consequence that the effectiveness of the material is very appreciably reduced.

We have found that we can eliminate and overcome the above-mentioned serious defects by applying a coating comprising an oil-modified glyptal resin, such as a drying oil-modified glyptal resin, and preferably a perilla oil-modified glyptal resin, between the base and the moistureproof surface coating, whereby the former is anchored to the latter.

By the expression anchors" or equivalent thereof used herein is meant the securingof the moistureproof coating imposed on the base, so that the product will withstand the deleterious eifect of water or moisture to a degree greater 5 than a similar product in which the intermediate coating is not present.

It is therefore an object of this invention to provide an article of manufacture preferably suitable for use as a wrapping tissue, wherein the moistureproof coating is anchored to the base by means of a composition containing an oil-modified glyptal resin disposed between the surface coating and the base.

A specific object of the instant invention is to provide a material suitable for use as a wrapping tissue comprising a base having a smooth, dense and non-porous surface, a coating containing a perilla oil-modified glyptal resin thereon and a moistureproof coating disposed on the oil-modifled glyptal resin, whereby the said moistureproof coating is anchored to the base.

A further object of this invention is to provide a method of producing amoistureproof material in which the moistureproof surface coating is anchored to the base.

In accordance with the instant invention, there Is provided an article of manufacture which comprises a base having a moistureproof surface coating and a coating comprising an oil-modified glyptal resin disposed intermediate said base and surface coating to anchor said .moistureproof surface coating to said base. V

As the base, this invention contemplates any material which is non-porous; smooth, dense and quite impermeable to the moistureproofing compositions. When such materials are moistureproofed by coating with the chosen composition, the latter will not penetrate therethrough or thereinto, but will normally result in a surface coating. Sheets or films of regenerated cellulose, chemically treated papers, for example,

papers which have been partly or wholly gelatinized and/or regenerated, highly calendered papers and glassine papers, may be cited as illustrative examples. In the preferred form of the invention, the base is also transparent.

As the moistureproofing composition, the instant invention contemplates any moistureproofing composition which would normally deposit a non-tenaciously adhering film on the untreated base and which contains one or more substances which wets the anchoring coating and/or unites therewith. Moistureproofing compositions com- I prising a cellulose derivative, a wax and a solvent or solvent mixture, with or without gums or resins, and optionally a plasticizer, are cited as illustrative examples. In the preferred embodiment a moistureproofing composition comprising a cellulose derivative, a gum or resin, a wax and a plasticizer of the type specifically set forth in Patent No. 1,826,696 is used.

As evident from the foregoing, the surface moistureproof coating is'anchored to the base by means of a coating disposed intermediate the base and the surface coating. The anchoring coatings contemplated by the instant invention are formed of oil-modified glyptal resins, such as drying oil-modified glyptal-resins, for example, a linseed oil-modified glyptal resin, China-wood oilmodified glyptal resin, and preferably a perilla oil-modified glyptal resin. These coatings are deposited usually at elevated temperatures from solutions of the resins in appropriate solvents. In order to more fully explain the composition of the anchoring coating media, there are hereafter set forth several compositions containing the oil-modified glyptals and the methods of preparing the same. It is, of course, to be understood that the invention is not restricted to these precise examples, since obviously various modifications may be made therein without departing from the nature or spirit of the instant invention.

Example I.--This composition comprises a perilla oil-modified glyptal resin and a solvent or diluent, suchas ethyl acetate. The perilla oilmodified glyptal resin is prepared as hereafter described from the following ingredients in approximately the proportions given:

. Parts Perilla oil 329.0 Phthalic anhydride 472.5 Glycerin 204.6 Sodium hydroxide 0.7 Metallic cobalt (added as linoleate) 0.7

The glyptal is prepared by heating 72.6 parts of C. P. glycerin to approximately 350 F. in a closed kettle equipped with a condenser and agitator. At 350 F. the sodium hydroxide is added, followed by the perilla oil. The mixture is then heated with rapid. stirring to 437 F., at which temperature it is maintained until the mass is clear and homogeneous. vThis takes approximately 15 to 30 minutes. The phthalic anhydride is then added and the mixture heated to approximately 392 F. At this point the remainder of the glycerin is added and the mixture reheated to 392 F. where it is held for approximately 5 hours or until the acid number is reduced to 45 or 55. The mixture is cooled quickly to 175 F. and diluted with a liquid carrier or solvent, such as 800 parts of ethyl acetate. The cobalt drier is then added and the solution clarified by suitable means. v

Example II.--This composition is a modification of that set forth in Example I and is prepared from the following ingredients in approximately the proportions given:

I Parts Perilla oil 168.2 Phthalic anhydride 303.4 Glycerin 131.0 Sodium hydroxide 0.4 Metallic cobalt (added as linoleate) 0.45

This composition is prepared by heating 37 parts of C. P. glycerin to 350 F. in a closed kettle fitted with a condenser and agitator. At 350 F. the sodium hydroxide is added, followed by the perilla oil, and the mixture heated to 437 F. with rapid stirring. When the mixture becomes clear and homogeneous, which usually takes from 15 to 30 minutes, the phthalic anhydride is added and the mixture heated to 392 F. The remaining glycerin is added, the mixture heated back to 392 F. and held for 4 hours or until the acid number becomes to 75. After cooling to 170 F., the mixture is diluted with the desired liquid vehicle, such as, for example, 480 parts of ethyl acetate. -The drier is then added and the solution clarified in a suitable manner. The resulting composition contains approximately 50% solids.

Example III.--This composition is also a modification of Example I and is prepared from the following ingredients in approximately the proportions given:

This composition is prepared by heating 61.5 parts of C. P. glycerin to 350 F. in a closed kettle fitted with a condenser and agitator. At 350 F., the sodium hydroxide is added, followed by the perilla oil, and the mixture heated to 437 F. with rapid stirring. When the mixture becomes clear and homogeneous (15 to 30 minutes), the phthalic anhydride is added and the mixture heated to 392 F. The remaining glycerin is added, the mixture heated back to 392 F. and held for 2 hours, when the acid number becomes 105 to 115. After cooling to 170 F., the mixture is diluted with 960 parts of ethyl acetate, the drier is added, and the solution clarified in a suitable manner. The resulting product contains 50% solids.

Example [V.This composition illustrates a linseed oil-modified glyptal resin which is prepared from the following ingredients in approximately the proportions given:

D Parts Linseed oil acids 30.96 Phthalic anhydride 46.31 Glycerin i. 22.73

The resin ingredients are charged into an open kettle and heated to 225 C. over a period of 1 hour. The mixture is held at thattemperature for 2% to 2% hours, during which time a. slow stream of carbon dioxide gas is bubbled through Parts China-wood 011 acids 30.96 Phthalic anhydride 46.31 Glycerin 22.73

The ingredients, together with enough xylene to make a ratio of 5 parts of resin to 1 part xylene are charged in an apparatus adapted for the continuous removal of the water formed in the reaction with simultaneous circulation and return of the xylene, and the entire mass is heated to boiling until finished, that is, until no more water distills from the mixture. Butyl acetate is then added together with additional xylene in such a manner that the final product is composed of 50% solids in equal parts of butyl acetate and xylene. The final acid number of the solid residue obtained by evaporation of the solvents is 59 to 60. The resin is dissolved in a solvent in such proportions as to give the desired concentration.

Example VI.-This composition illustrates a glyptal resin modified by both linseed oil and China-wood oil and is prepared from the following ingredients in approximately the proportions given:

Parts Linseed oil acids 31.15 China-wood oil acids 12.46 Phthalic anhydride 36.52

Glycerin 19.87

,cedure which has given satisfactory results.

Theingredients are heated in an open vessel to 225 C. over a period of 1 to 1% hours. It held for 2 to 3%; hours at this temperature and blown slowly with a stream of carbon dioxide gas, the final acid number is 25 to 38. Obviously, the higher acid number is obtained if the shorter heating period is used. The resin is dissolved in an appropriate quantity of solvent to give a composition of the desired concentration.

It is to be understood that the resins may be diluted or dissolved in any appropriate solvent and that the invention is not restricted to any specific solvent or proportions of the ingredients constituting the composition. Likewise, any suitable modifying agent may also be incorporated in the composition.

For purpose of illustration, the method constituting another phase of this invention will be described in connection with'sheets or films of regenerated cellulose. i

In accordance with one embodiment of the method, a sheet or film of regenerated cellulose is coated in any suitable manner, such as, for

example, by immersing, spraying or flowing a solution of the anchoring coating medium. The coated material is then dried at an elevated temperature, the specific temperature depending on the boiling point of the solvent, and thereafter the selected moistureproofing composition is applied and the coated material treated as set forth in Patent No. 1.826.699.

The dried anchor coating is transparent and of such a thickness as to not materially increase the thickness of the final product. Satisfactory results have been secured when the dried anchor coating was one ten-thousandth of an inch thick (both sides).

It is to be noted that in order to secure optimum results, the anchor coating should be thoroughly dried prior to the application of the moistureproofing composition and the latter should contain a substance which wets the anchor coating and/or unites thereto. The drying of the anchor coating includes not only the removal of the solvent but also an actual change in chemical composition of the composition by oxidation.

It has been found that a better anchoring is secured when the sheet or film of regenerated cellulose contains approximately 5% to 7% or more and preferably 6% to 6%,% of moisture at the time the moistureproofing composition is applied. With this in view, the process also contemplates subjecting the sheet or film of regenerated cellulose coated with the dried anchoring medium, and prior to the application of the moistureproofing composition, to a suitable treatment, whereby the moisture content of the film is increased or decreased as may be necessary to that desired. Thus, for example, when the film contains a moisture content of approximately 4% to 5% or less, the film may be subjected to a humidifying treatment. Conversely, when the film contains a moisture content of approximately 8% to 9% or more, the film is treated as by heating to remove the moisture in excess of that desired.

The sheet or film of regenerated cellulose, prior to the application of the anchor coating, may need to be humidified, or dried, depending upon its moisture content which may have to be increased or decreased according to the conditions under which it has been stored.

Hereinafter, there is set forth a specific pro- In accordance with this procedure, a sheet or film of plain, transparent regenerated cellulose is led coating composition and thence to adrying tower where the coating is thoroughly dried as previously explained. The coated film is then subjected to a humidifying treatment, whereby the moisture content thereof is modified so as to range from 5% to 7% and preferably 6% to (l If the moistureproofing composition is applied immediately, no further humidification of the film is necessary. If, however, the anchor coated film is stored for a period of time, depending upon the conditions under which it has been stored, it may be necessary to either dry or rehumidify slightly prior to coating said film with the moistureproofing lacquer in order that the moisture content of said film may be adjusted to that desired, i. e.-5% to 7% and preferably 6% to 6 5%. After the moistureproofing composition has been applied, the film is subjected to the same treatments as set forth in the Charch and Prindle Patent No. 1,826,699, 1. e. subjecting the coated material to a temperature at least equal to the melting or crystallization point of the wax or waxes in the composition and then subjecting the coated film to a humidifying treatment.

The product resulting from the process just described comprises a material in which the surface coating is anchored to the base. It resists the transmission or difiusion of water vapor therethrough to an extent at least 7 times, and preferably 10, 15, 20, 30, 50, 100 or even several hundred times, as great as that of the uncoated materials when tested under the same conditions. It is not seriously affected when brought in contact with materials containing a relatively high moisture content or water. Tests have shown that the material of the instant invention may be immersed or suspended in water at room temperature without the moistureproof surface coating becoming loose enough to be rubbed off the base by the fingers for a period which is 10, 20, 30, 40, 50, 100,150, 200 or even more times greater. than regenerated cellulose coated with the surface coating, but without the anchoring coating. In addition to the aforementioned desirable characteristics, the product is characterized by a high degree of flexibility, good surface slip, nongreasiness and preferably also a glass-clear transparency. It is, of course, understood that colored transparent materials may be secured by incorporating a suitable dyestuif in the moistureproof coating and/or utilizing an appropriately colored base. Opaque colored materials may be secured by incorporating a suitable opacity-inducing agent, either colored or in admixture with the desired coloring, as for example, a pigment in the moistureproof surface coating or by using a colored opaque base.

Since it is obvious that various modifications and changes may be made in the specific details above described, this invention is not restricted thereto except as set forth in the appended claims.

We claim:

1. A wrapping tissue comprising a sheet or film of a cellulosic material having a smooth, dense and non-porous surface, a moistureproof surface coating thereon, and a coating comprising an oil-modified glyptal disposed between said sheet or film and surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the cellulosic base and the moistureproof coating.

2. A wrapping tissue comprising a sheet or film of a cellulosic material having a smooth, dense and non-porous surface, a moistureproof surface coating thereon, and a coating comprising a drying oil-modified glyptal disposed between said sheet or film and surface coating to anchor said surface coating to said sheet or film, and render thetissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at-least ten times greater than a tissue consisting of the cellulosic base and the moistureproof coating.

3. A wrapping tissue comprising a sheet or film of a cellulosic material having a smooth, dense and non-porous surface, a moistureproof surface coating thereon, and a coating comprising a perilla oil-modified glyptal disposed between said sheet or film and surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the cellulosic base and the moistureproof coating.

4. A wrapping tissue comprising a sheet or film of a cellulosic material having a smooth, dense and non-porous surface, a moistureproof surface coating thereon, and a coating comprising a linseed oil-modified glyptal disposed between said sheet or film and surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the cellulosic base and the moistureproof coating.

5. A wrapping tissue comprising a sheet or film of a cellulosic material having a smooth, dense and non-porous surface, a moistureproof surface coating thereon, and a coating comprising a China-wood oil-modified glyptal disposed between said sheet or film and surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the .cellulosic base and the moistureproof coating.

6. A wrapping tissue comprising a sheet or film of regenerated cellulose, a moistureproof surface coating thereon, and a coating comprising an oil-. modified glyptal disposed between said sheet or film and surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a'period of time, which is at least ten times greater than a tissue consisting of the regenerated cellulose base and the moistureproof coating.

7. A wrapping tissue comprising a sheet or film of regenerated cellulose, a moistureproof surface coating thereon, and a coating comprising a drying oil-modified glyptal disposed between said sheet or film and surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the regenerated cellulose base and the moistureproof coating.

8. A wrapping tissue comprising a sheet or film of regenerated cellulose, a moistureproof surface coating thereon, and a coating comprising a perilla oil-modified glyptal disposed between said sheet or film and surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action. of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the regenerated cellulose base and the moistureproof coating.

9. A wrapping tissue comprising a sheet or film of regenerated cellulose, a, moistureproof surface coating thereon, and a coating comprising a linseed oil-inodified glyptal disposed between said sheet or film and surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the regenerated cellulose base and the moistureproof coating.

10. A wrapping tissue comprising a sheet or film of regenerated cellulose, a moistureproof surface coating thereon, and a coating comprising a China-wood oil-modified glyptal disposed between said sheet or film and surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the regenerated cellulose base and the moistureproof coating. v

11. In a method of preparing moistureproof materials, the steps which comprise coating a sheet or film of regenerated cellulose with a composition containing an oil-modified glyptal, drying the coating and modifying the moisture content of the coated material prior to the application of the moistureproofing composition.

12. In a method of preparing moistureproof materials, the steps which comprise coating a sheet or film of regenerated cellulose with a composition containing a drying oil-modified glyptal, drying the coating and modifying the moisture content of the coated material prior to the application of the moistureproofing composition.

13. In a method of preparing moistureproof materials, the steps which comprise coating a sheet or film of regenerated cellulose with a composition containing a perilla oil-modified glyptal, drying the coating and modifying the moisture content of the coated material prior to the application of the moistureproofing composition.

14. In a method of preparing moistureproof materials, the steps which comprise coating a sheet or film of regenerated cellulose with a composition containing a linseed oil-modified glyptal, drying the coating and modifying the moisture content of the coated material prior to the application of the moistureproofing composition.

15. In a method of preparing moistureproof materials, the steps which comprise coating a sheet or film of regenerated cellulose with a composition containing a China-wood oil-modified glyptal, drying the coating and modifying the moisture content of the coated material prior to the application of the moistureproofing composition.

16. In a method of preparing moistureproof materials, the steps which comprise coating a sheet or film of regenerated cellulose with a composition containing an oil-modified glyptal, drying the coating, and modifying the moisture content of the coated material until it constitutes 5%7% of the sheet or film of regenerated cellulose prior totheappiicationofthemoishireproofing compo- I sition.

17. In a method of preparing moistureproof materials, the steps which comprise coating a sheet or film of regenerated cellulose with a composition containing a drying oil-modified glyptal, drying the coating, and modifying the moisture content of the coated material until it constitutes 5%-7% of the sheet or film of regenerated cellulose prior to the application of the moistureproofing composition.

18. In a method of preparing moistureproof materials, the steps which comprise coating 9. sheet or film of regenerated cellulose with a composition containing a perilla oil-modified glyptal, drying the coating, and modifying the moisture content of the coated material until it constitutes 5%-7% of the sheet or film of regenerated cellulose prior to the application of the moistureproofing composition.

19. In a method of preparing moistureproof materials, the steps which comprise coating a sheet or film of regenerated cellulose with a composition containing a linseed oil-modified glyptal, drying the coating, and modifying the moisture content of the coated material until it constitutes 5%-7% of the sheet or film of regenerated cellulose prior to the application of the moistureproofing composition.

20. In a method of preparing moistureproof materials, the steps which comprise coating a sheet or film of regenerated cellulose with a composition containing a China-wood oil-modified glyptal, drying the coating, and modifying the moisture content of the coated material until it constitutes 5%-7% of the sheet or film of regenerated cellulose prior to the application of the moistureproofing composition.

21. In a method of preparing moistureproof materials, the steps which comprise subjecting a sheet or film of regenerated cellulose to a humidiiying treatment, coating saidsheet or film with a composition containing an oil-modified glyptal, drying the coating, and modifying the moisture content of the coated material prior to the application of the moistureprooflng composition.

22. In a method of preparing moistureproof materials, the steps which comprise subjecting a sheet or film of regenerated cellulose to a humidifying treatment, coating said sheet or film with a composition containing a drying oil-modified glyptal, drying the coating, and modifying the moisture content of the coated material prior to the application of the moistureproofing composition.

23. In a method of preparing moistureproof materials, the steps which comprise subjecting a sheet or film of regenerated cellulose to a humidifying treatment, coating said sheet or film with a composition containing a perilla oil-modified glyptal, drying the coating, and modifying the moisture content of the coated material prior to the application of the moistureproofing composition.

24. In a method of preparing moistureproof materials, the steps which comprise subjecting a sheet or film of regenerated cellulose to a humidifying treatment, coating said sheet or film with a composition containing a linseed oil-modified glyptal, drying the coating, and modifying the moisture'content of the coated material prior to the application of the moistureproofing composition.

25. In a method of preparing moistureproof materials, the steps which comprise subjecting a sheet or film of regenerated cellulose to a humidifying treatment, coating said sheet or film with a composition containing a China-wood oil-modified glyptal, drying the coating, and modifying the moisture content of the coated material prior to the application'of the moistureproofing composition.

26. In a method of preparing moistureproof materials, the steps which comprise subjecting a sheet or film of regenerated cellulose to'a humidifying treatment, coating said sheet or film with a composition containing an oil-modified glyptal, drying the coating, and modifying the moisture content of the coated material until it constitutes 5%-7% of the sheet or film of regenerated cellulose prior to the application of the moistureproofing composition.

27. In a method of preparing moistureproof materials, the steps which comprise subjecting a sheet or film of regenerated cellulose to a humidifying treatment, coating said sheet or film with a composition containing a drying oil-modified glyptal, drying the coating, and modifying the moisture content of the coated material until it constitutes 5%-'i% of the sheet or film of regenerated cellulose prior to the application of the moistureproofing composition.

28. In a method of preparing moistureproof materials, the steps which comprise subjecting a sheet or film of regenerated cellulose to a humidifying treatment, coating said sheet or film with a composition containing a perilla oil-modified glyptal, drying the coating, and modifying the moisture content of the coated material until it constitutes 5%-'7% of the sheet or film of regenerated cellulose prior to the application of the moistureproofing composition.

29. In a method of preparing moistureproof materials, the steps which comprise subjecting a sheet or flim of regenerated cellulose to a humidiiying treatment, coating said sheet or film with a composition containing a linseed oil-modified glyptal, drying the coating, and modifying the moisture content of the coated material until it constitutes 5%-7% of the sheet or film of regenerated cellulose prior to the application of the moistureproofing composition.

30. In a method of preparing moistureproof materials, the steps which comprise subjecting a sheet or film of regenerated cellulose to a humidifying treatment, coating said sheet or film with a composition containing a China-wood oil-modified glyptal, drying the coating, and modifying the moisture content of the coated material until it constitutes 5%7% of the sheet or film of regenerated cellulose prior to the application of the moistureproofing composition.

31. A wrapping tissue comprising a transparentsheet or film of a cellulosic material having a smooth, dense and non-porous surface, a transparent moistureproof-surface coating thereon, and

a transparent coating comprising an oil-modified glyptal disposed between said sheet or film and surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of, the cellulosic base and the moistureproof coating.

32. A wrapping tissue comprising a transparent sheet or film of a cellulosic material having a smooth, dense and non-porous surface, a transparent moistureproof surface coating thereon, and a transparent coating-comprising a drying oil-modified glyptal disposed between said sheet or film and surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the cellulosic base and the moistureproof coating.

33. A wrapping tissue comprising a transparent sheet or film of a cellulosic material having a smooth, dense and non-porous surface, a transparent moistureproof surface coating thereon, and a transparent coating comprising a perilla oil-modified glyptal disposed between said sheet or film and surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the cellulosic base and the moistureproof coating.

34. A wrapping tissue comprising a transparent sheet or film of a cellulosic material having a smooth, dense and non-porous surface, a transparent moistureproof surface coating thereon, and a transparent coating comprising a linseed oil-modified glyptal disposed between said sheet or film and surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the cellulosic base and the moistureproof coating.

35. A wrapping tissue comprising a transparent sheet or film of a cellulosic material having a smooth, dense and non-porous surface, a transparent moistureproof surface coating thereon, and a transparent coating comprising a Chinawood oil-modified glyptal disposed between said sheet or film and surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the cellulosic base and the moistureproof coating.

36. A wrapping tissue comprising a sheet or film of a cellulosic material having a smooth, dense and non-porous surface,'a moistureproof surface coating on each side thereof, and a coating comprising an oil-modified glyptal disposed between said sheet or film and each surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the cellulosic base and the moistureproof coating, the total thickness of the anchor coating on both sides of the base sheet or film being one tenthousandths of an inch.

37. A wrapping tissue comprising a sheet or film of a cellulosic material having a smooth,

dense and non-porous surface, a moistureproof menses both sides of the base sheet or film being one ten-thousandths of an inch.

38. A wrapping tissue comprising a sheet or film of a cellulosic material having a smooth, dense and non-porous surface, a moistureproof surface coating on each side thereof, and a coating comprising a perilla oil-modified glyptal disposed between said sheet or film and each surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the cellulosic base and the moistureproof coating, the total thickness of the anchor coating on both sides of the base sheet or film being one tenthousandths of an inch.

39. A wrapping tissue comprising a sheet or film of a cellulosic material having a smooth, dense and non-porous surface, a moistureproof surface coating on each side thereof, and a coating comprising a linseed oil-modified glyptal disposed between said sheet or film and each surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature fora period of time, which is at least ten times greater than a tissue consisting of the cellulosic base and the moistureproof coating, the total thickness of the anchor coating on both sides of the base sheet or film being one ten-thousandths of an inch.

40. A wrapping tissue comprising a sheet or film of a cellulosic material having a smooth, dense and non-porous surface, a moistureproof surface coating on each side thereof, and a coating comprising a China-wood oil-modified glyptal disposed between said sheet or film and each surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the cellulosic base and the moistureproof coating, the total thickness of the anchor coating on both sides of the base sheet or film being one tenthousandths of an inch.

41. A wrapping tissue comprising a sheet or film of regenerated cellulose, a moistureproof surface coating on each side thereof, and a coating comprising an oil-modified glyptal disposed between said sheet or film and each surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the regenerated cellulose base and the moistureproof coating, the total thickness of the anchor coating on both sides of the base sheet or film being one ten-thousandths of an inch.

42. A wrapping tissue comprising a sheet or film of regenerated cellulose, a moistureproof surface coating on each side thereof, and a coating comprising a drying oil-modified glyptal disposed between said sheet or film and each surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the regenerated cellulose base and the moistureproof coating, the total thickness of the anchor coating on both sides of the base sheet or film being one ten-thousandths of an inch.

43. A wrapping tissue comprising a sheet or film of regenerated cellulose, a moistureproof surface coating on each side thereof, and a coating comprising a perilla oil-modified glyptal disposed between said sheet or film and each surface coating to anchor said surfacecoating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the regenerated cellulose base and the moistureproof coating, the total thickness of the anchor coating on both sides of the base sheet or film being one ten-thousandths of an inch.

44. A wrapping tissue comprising a sheet or film of regenerated cellulose, a moistureproof surface coating on each side thereof, and a coating comprising a linseed oil-modified glyptal disposed between said sheet or film and each surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the regenerated cellulose base and the moistureproof coating, the total thickness of the anchor coating on both sides of the base sheet or film being one ten-thousandths of an inch.

45. A wrapping tissue comprising a sheet or film of regenerated cellulose, a moistureproof surface coating on each side thereof, and a coating comprising a China-wood oil-modified glyptal disposed between said sheet or film and each surface coating to anchor said surface coating to said sheet or. film, and render the tissue capable' of withstanding the deleterious-action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the regenerated cellulose base and the moistureproof coating, the total thickness of the anchor coating on both sides of the base sheet or film being one ten-thousandths of an inch.

46. A wrapping tissue comprising a transparent sheet or film of a cellulosic material having a smooth, dense and non-porous surface, a transparent moistureproof surface coating on each side thereof, and a transparent coating comprising an oil-modified glyptal disposed between said sheet or film and each surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the cellulos ic base and the moistureproof coating, the total thickness of the anchor coating on both sides of the base sheet or film being one ten-thousandths of an inch.

47. A wrapping tissue comprising a transparent sheet or film: of a cellulosic material having a smooth, dense and non-porous surface, a transparent moistureproof surface coating on each side thereof, and a transparent coating comprising a drying oil-modified glyptal disposed between said sheet or film and each surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the cellulosic base and the moistureproof coating, the total thickness of the anchor coating on both sides of the base sheet or film being one ten-thousandths of an inch.

48. A wrapping tissue comprising a transparent sheet or film of a cellulosic material having a smooth, dense and non-porous surface, a transparent moistureproof surface coating on each side thereof, and a transparent coating comprising a perilla oil-modified glyptal disposed between said sheet or film and-each surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for thereof, and a transparent coating comprising a linseed oil-modified glyptal disposed between said sheet or film and each surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the cellulosic base and the moistureproof coating, the total thickness of the anchor coating.on both sides of the basesheet or film being one ten-thousandths of an inch.

50. A wrapping tissue comprising a transparent sheet or film of a cellulosic material having a smooth, dense and non-porous surface, a transparent moistureproof surface coating on each side thereof, and a transparent coating comprising a China-wood oil-modified glyptal disposed be- I tween said sheet or film and each surface coating to anchor said surface coating to said sheet or film, and render the tissue capable of withstanding the deleterious action of water at room temperature for a period of time, which is at least ten times greater than a tissue consisting of the 7 I cellulosic base and the moistureproof coating, the total thickness of the anchor coating on both sides of the base sheet or film being one ten-thou sandths of an inch. 1

WILLIAM HALE CHARCH.

WILLIAM L. HYDEN.

JOHN C. SIEMANN. 

